Recently, radiobroadcasters have begun providing their audio content over the internet. Listeners can receive and play the audio content with a number of currently available devices. For example, a home listener can receive and play audio content or “netcasts” with a personal computer (“PC”) based device. PC based devices generally include a PC, an internet account, a browser software such as Internet Explorer® or Netscape Navigator®, an audio processing software “plug-in” capable of processing audio information, and a radio simile graphical interface. Listeners can also receive and play netcasts with devices known as internet appliances. In our co-pending application, Internet Radio Receiver and Interface, U.S. application Ser. No. 09/334,846, we describe a radio receiver like internet appliance having all the necessary components to receive and play audio content over the internet.
Audio files provided by internet radiobroadcasters are typically large and if downloaded as a whole could take several minutes of wait time for each one minute of audio play time. A process called streaming audio allows the user to listen to the audio continuously after a buffer is filled with audio data (as opposed to downloading the audio file and playing the file after the download is complete). A percentage of the streaming audio data file is temporarily stored in the buffer until it is transferred for outputting. There are a number of streaming audio formats available. The common ones today include Real Networks G2 and G7, Microsoft Windows Media, Shoutcast MP3 and Icecast MP3.
When a listener using the PC based device changes from one internet radio station to another, the PC based device must (a) stop playing from the current station and flush the buffer, (b) establish a data connection with the new station, (c) receive and fill the buffer with streaming data from the new station, (d) start decoding the streaming data, and (e) start playing the streaming data from the head of the buffered data while adding new streaming audio data to the tail of the buffered data. Step (c) is commonly called buffering or pre-buffering and may take on the order of several seconds depending on the user's connection quality to the network, the network traffic, and the characteristics of the streaming audio to which the user is trying to connect. The buffering process results in a delay in audio output, resulting in a period of silence referred to as dead air time. Currently, this dead air time is filled with silence. Where the audio to presented through a PC with a display, it is visually represented on the PC screen with a small progress bar. Because the user hears no audio during the buffering process, the progress bar is a crucial element. Savvy PC based device users are accustomed to such delays in getting access to audio content.
On the other hand, users listening to audio on a radio receiver are not accustomed to delays in getting access to the audio. When a user switches radio stations on the radio receiver, the user expects the radio receiver to respond quickly with the audio from the new radio station. The radio receiver user experiences little, if any, dead air time. Our internet radio appliances mimic the functionality of traditional AM/FM radios, allowing the user to listen to internet “radio stations” through an appliance that does not require a fully functional personal computer, and instead functions in a manner similar to the traditional radio receiver. Because our internet appliances mimic typical radio receivers, users will expect the internet appliance to respond quickly with audio. The user will expect little, if any, dead air time.
However, when the user changes internet radio stations on an internet appliance, the internet appliance also undergoes the buffering or pre-buffering process described above. Communicating the progress of the buffering process to the user is difficult on the internet appliance since the user is not sitting in front of a computer screen, and the internet appliance preferably has a minimal graphical interface. The internet appliance generally has simple knobs and buttons, and the user may or, ideally, may not be presented with a progress bar. Silence or dead air time experienced on the internet appliance is annoying and potentially confusing to the user. The user will not know whether the internet appliance is still connected to the internet or if the internet appliance has encountered some obstacle to connection with a desired netcaster. The user's listening experience is diminished by this dead air time. In the embodiment of our internet radio system, the dead air time is unacceptable.